Interacciones Tróficas entre Trucha Arco Iris (Oncorhynchus Mykiss), Pejerrey Patagónico (Patagonina Hatcheri) y Perca (Percichthys Trucha) en un Ambiente Patagónico

Abstract

Trophics interactions between rainbow trout (Oncorhynchus mykiss), patagonic silverside (Patagonina hatcheri) and perch (Percichthys trucha), in a patagonic pond. This paper addresses the problem of identifying trophics links between O. mykiss, an elxotic species, and two other native ones, P. hatcheri and P. trucha in the Terraplen pond (Austral Subregion, Patagonic Biogeografic Province). Results were processed by using conventional methodology and multivariate analysis (principal components and correspondence). Relevant conclusions are: the studied species can be considered as opportunistic and generalist feeders. The juvenile fishes prey on the zooplankton comunity, while the adults specimens prey on tbe benthos. Comparisons made among several environments showed that there is a great deal of flexibility in the feeding habits of these species. Moreover, a relationship was found between relative fish biomass (as kg/catch with standard gill net) and diet overlap. The multivariate analysis allowed the discrimination of the diet habits: O. mykiss mainly consumed Amphipoda. P. hatcheri consumed Pellecypoda and P. trucha preyed on Chironomidae larvae.